﻿// Upgrade NOTE: replaced 'mul(UNITY_MATRIX_MVP,*)' with 'UnityObjectToClipPos(*)'

Shader "[FC Effect]/GrabPassBlur"
{
	Properties
	{
		_Color("Main Color", Color) = (1,1,1,1)
		_BumpAmt("Distortion", Range(0,128)) = 10
		_Size("Size", Range(0, 20)) = 1
		_MainTex("Tint Color (RGB)", 2D) = "white" {}
		_BumpMap("Normalmap", 2D) = "bump" {}
	}

	Category
	{
		// We must be transparent, so other objects are drawn before this one.
		Tags{ "Queue" = "Transparent" "IgnoreProjector" = "True" "RenderType" = "Opaque" }

		SubShader
		{
			// Horizontal blur
			GrabPass
			{
				Tags{ "LightMode" = "Always" }
			}

			Pass
			{
				Tags{ "LightMode" = "Always" }

				CGPROGRAM
				#pragma vertex vert
				#pragma fragment frag
				#pragma fragmentoption ARB_precision_hint_fastest
				#include "UnityCG.cginc"

				struct appdata_t
				{
					float4 vertex : POSITION;
					float2 texcoord: TEXCOORD0;
				};

				struct v2f
				{
					float4 vertex : POSITION;
					float4 uvgrab : TEXCOORD0;
				};

				v2f vert(appdata_t v)
				{
					v2f o;
					o.vertex = UnityObjectToClipPos(v.vertex);
					#if UNITY_UV_STARTS_AT_TOP
					float scale = -1.0;
					#else
					float scale = 1.0;
					#endif
					o.uvgrab.xy = (float2(o.vertex.x, o.vertex.y * scale) + o.vertex.w) * 0.5;
					o.uvgrab.zw = o.vertex.zw;
					return o;
				}

				sampler2D _GrabTexture;
				float4 _GrabTexture_TexelSize;
				float _Size;

				half4 frag(v2f i) : COLOR
				{
					//half4 col = tex2Dproj( _GrabTexture, UNITY_PROJ_COORD(i.uvgrab));
					//return col;

					half4 sum = half4(0,0,0,0);
					#define GRABPIXEL(weight,kernelx) tex2Dproj( _GrabTexture, UNITY_PROJ_COORD(float4(i.uvgrab.x + _GrabTexture_TexelSize.x * kernelx*_Size, i.uvgrab.y, i.uvgrab.z, i.uvgrab.w))) * weight
					sum += GRABPIXEL(0.05, -4.0);
					sum += GRABPIXEL(0.09, -3.0);
					sum += GRABPIXEL(0.12, -2.0);
					sum += GRABPIXEL(0.15, -1.0);
					sum += GRABPIXEL(0.18,  0.0);
					sum += GRABPIXEL(0.15, +1.0);
					sum += GRABPIXEL(0.12, +2.0);
					sum += GRABPIXEL(0.09, +3.0);
					sum += GRABPIXEL(0.05, +4.0);

					return sum;
				}
				ENDCG
			}

			// Vertical blur
			GrabPass
			{
				Tags{ "LightMode" = "Always" }
			}

			Pass
			{
				Tags{ "LightMode" = "Always" }

				CGPROGRAM
				#pragma vertex vert
				#pragma fragment frag
				#pragma fragmentoption ARB_precision_hint_fastest
				#include "UnityCG.cginc"

				struct appdata_t
				{
					float4 vertex : POSITION;
					float2 texcoord: TEXCOORD0;
				};

				struct v2f
				{
					float4 vertex : POSITION;
					float4 uvgrab : TEXCOORD0;
				};

				v2f vert(appdata_t v)
				{
					v2f o;
					o.vertex = UnityObjectToClipPos(v.vertex);
					#if UNITY_UV_STARTS_AT_TOP
					float scale = -1.0;
					#else
					float scale = 1.0;
					#endif
					o.uvgrab.xy = (float2(o.vertex.x, o.vertex.y * scale) + o.vertex.w) * 0.5;
					o.uvgrab.zw = o.vertex.zw;
					return o;
				}

				sampler2D _GrabTexture;
				float4 _GrabTexture_TexelSize;
				float _Size;

				half4 frag(v2f i) : COLOR
				{
					//half4 col = tex2Dproj( _GrabTexture, UNITY_PROJ_COORD(i.uvgrab));
					//return col;

					half4 sum = half4(0,0,0,0);
					#define GRABPIXEL(weight,kernely) tex2Dproj( _GrabTexture, UNITY_PROJ_COORD(float4(i.uvgrab.x, i.uvgrab.y + _GrabTexture_TexelSize.y * kernely*_Size, i.uvgrab.z, i.uvgrab.w))) * weight
					//G(X) = (1/(sqrt(2*PI*deviation*deviation))) * exp(-(x*x / (2*deviation*deviation)))

					sum += GRABPIXEL(0.05, -4.0);
					sum += GRABPIXEL(0.09, -3.0);
					sum += GRABPIXEL(0.12, -2.0);
					sum += GRABPIXEL(0.15, -1.0);
					sum += GRABPIXEL(0.18,  0.0);
					sum += GRABPIXEL(0.15, +1.0);
					sum += GRABPIXEL(0.12, +2.0);
					sum += GRABPIXEL(0.09, +3.0);
					sum += GRABPIXEL(0.05, +4.0);
					return sum;
				}
				ENDCG
			}

			// Distortion
			GrabPass
			{
				Tags{ "LightMode" = "Always" }
			}

			Pass
			{
				Tags{ "LightMode" = "Always" }

				CGPROGRAM
				#pragma vertex vert
				#pragma fragment frag
				#pragma fragmentoption ARB_precision_hint_fastest
				#include "UnityCG.cginc"

				struct appdata_t
				{
					float4 vertex : POSITION;
					float2 texcoord: TEXCOORD0;
				};

				struct v2f
				{
					float4 vertex : POSITION;
					float4 uvgrab : TEXCOORD0;
					float2 uvbump : TEXCOORD1;
					float2 uvmain : TEXCOORD2;
				};

				float _BumpAmt;
				float4 _BumpMap_ST;
				float4 _MainTex_ST;

				v2f vert(appdata_t v)
				{
					v2f o;
					o.vertex = UnityObjectToClipPos(v.vertex);
					#if UNITY_UV_STARTS_AT_TOP
					float scale = -1.0;
					#else
					float scale = 1.0;
					#endif
					o.uvgrab.xy = (float2(o.vertex.x, o.vertex.y * scale) + o.vertex.w) * 0.5;
					o.uvgrab.zw = o.vertex.zw;
					o.uvbump = TRANSFORM_TEX(v.texcoord, _BumpMap);
					o.uvmain = TRANSFORM_TEX(v.texcoord, _MainTex);
					return o;
				}

				fixed4 _Color;
				sampler2D _GrabTexture;
				float4 _GrabTexture_TexelSize;
				sampler2D _BumpMap;
				sampler2D _MainTex;

				half4 frag(v2f i) : COLOR
				{
					// calculate perturbed coordinates
					half2 bump = UnpackNormal(tex2D(_BumpMap, i.uvbump)).rg; // we could optimize this by just reading the x  y without reconstructing the Z
					float2 offset = bump * _BumpAmt * _GrabTexture_TexelSize.xy;
					i.uvgrab.xy = offset * i.uvgrab.z + i.uvgrab.xy;

					half4 col = tex2Dproj(_GrabTexture, UNITY_PROJ_COORD(i.uvgrab));
					half4 tint = tex2D(_MainTex, i.uvmain) * _Color;

					return col * tint;
				}
				ENDCG
			}
		}
	}
}